Eminem is losing it with a New Zealand political party! His court case against the country's conservative National Party for their infringement of Lose Yourself in a 2014 ad campaign began on Monday!

His legal team argues the stock music track titled Eminem-esque breaches his copyright, and they've got proof. According to the Detroit native's lawyer Gary Williams, emails reveal party members were aware of what they were doing, with one writing:

"I guess the question we're asking, if everyone thinks it's Eminem, and it's listed as 'Eminem-esque,' how can we be confident that Eminem doesn't say we're ripping him off?"

And as Gary mentioned in his opening statements during the first day of trial:

"'Lose Yourself' is an extremely valuable song. The licensing of the song has been extremely carefully controlled. Despite many requests, it has only rarely been licensed for advertising purposes. When licensed, it can command in the millions of dollars. That's how valuable it is."

The National Party denies any wrongdoing. The trial is said to last only a week, so we'll let you know how this turns out soon!

In the meantime, check out some other seriously questionable feuds (below)…

The 21-year-old is currently a student at Michigan State University, and appears to enjoy the same things as other women her age — taking selfies, posting inspirational quotes, and sharing photos of her hot boyfriend and adorable puppy!

The 41-year-old mom to three avoided a trial by pleading guilty, and was sentenced to one year of probation and ordered to pay $900 in fines. Additionally, she must undergo random drug and alcohol testing.

Eminem's baby momma confessed in court:

"I didn't take into consideration the safety of others and the feelings of my family and I'm truly sorry… I just want to put this all behind me."